Bitter Cold Wind Chills Follow Departing Northeast Storm; Heavy Snow and High Winds in the West

Areas of heavy snow will linger across portions of New England and downwind of the Great Lakes into Monday. Bitter cold and gusty winds behind the departing storm are resulting in dangerous wind chill temperatures for much of the Northeast corner of the U.S. In the west, heavy mountain snow will impact portions of Utah and Wyoming with high winds in the southwest Monday.
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Spotter Training Materials

It is important to note that reviewing the information and slides contained on this web page is NOT considered a substitute to actually attending a spotter training course. This web page is intended to be a supplement to the spotter training courses conducted by the NWS Norman every year. These typically occur in January to March, prior to the main severe weather season. New schedules are released every year around late December or early January. You can check the NWS Norman News on the home page where information will be provided when spotter schedules are announced.

Why are storm spotters so crucial?
The doppler radars that the National Weather Service uses are extremely useful in diagnosing thunderstorms. However, they cannot tell us what is occurring in the lowest levels of the storm (i.e. where a tornado would likely occur). This problem is due to the curvature of the Earth; the radar beam will get higher above the surface the further it gets from the radar site. Meteorologists can analyze the radar data and determine whether the storm is a threat, but only spotters can report what is actually happening. Therefore, spotter reports give us crucial information.

What should I report?
You should report hail over 3/4" in diameter, wind gusts of 58 mph or more, wind damage, tornadoes, and/or flooding. Click the images below for further information.

Here are some reporting tips!
We use spotter reports during severe weather for many things, so it is very important that you be as accurate as possible with your report. Report only what you see - not what you think will happen, etc. Be careful when you choose words to describe what you are seeing, especially related to damage. There is a big difference between a house that is destroyed and a house that just has its roof torn off! Don't overstate the significance of what you are observing.

How do I know where to find the severe weather?
Typically you should look for the area where the updraft and downdraft regions of the storm meet. This will vary based on the type of storm you encounter. For a graphical representation of these scenarios, reference the slides below. You can differentiate between an updraft region and a downdraft region based on visual clues. An updraft region will have upward motion, inflow and cloud formation. A downdraft region will have downward motion and outflow; this will be where you usually find hail, wind and rain.

If I'm a mobile spotter, how do I position myself to view the storm safely?
Always position yourself so you have a good view of the updraft region of the storm. This is where severe weather is most likely to occur, and it will keep you out of the downdraft region of the storm where you could be in danger from downburst winds and severe hail. When positioning yourself in the updraft region, be sure not to get too close to the area of rotation/"interest". Always keep yourself a safe distance away.

What should I expect to see and indentify on a squall line?
You should have positioned yourself in the updraft region of the storm, in this case along the leading edge of the squall line. In most cases, there will be a shelf cloud present that indicates the boundary between the updraft region and downdraft region of the storm. Tornadoes are infrequent in squall lines; usually the primary threat will come from gusty winds and perhaps hail.

What should I expect to see and indentify on a supercell?
If you are in the updraft region of a supercell, then you should have a good view of any of the features shown in the slides below. Review the slides for more information. One of the most common spotter mistakes is reporting scud clouds (non-rotating, ragged clouds below the main cloud base) as funnel clouds or wall clouds. Be sure to watch any feature you suspect may be rotating for several minutes to validate your thinking. Remember, when looking for the "action area" in a supercell, find a rain-free base.